1. Technical Field
The present invention relates to a light source device and a projector.
2. Related Art
In related art, a light source device including plural solid-state light sources, plural collimator lenses that respectively nearly parallelize lights from the plural solid-state light sources, and a collection system that collects light from the plural collimator lenses has been known (for example, Patent Document 1 (JP-A-2010-78975)). According to the light source device in related art, the plural solid-state light sources are provided and high-intensity light can be output.
However, in the light source device in related art, there has been a problem that, for handling of the lights from the plural solid-state light sources, the downstream optical elements (the collection system, an integrator system, etc.) become larger and reduction in size and weight of the light source device becomes difficult.
FIG. 9 is a top view showing an optical system of a projector 900 according to a related earlier application. The sign 901 denotes an illumination device and the sign 902 denotes a light source device.
The inventors of the invention have diligently made further studies for solving the problem, and, as a result, had a thought of a light source device further including “a reflection part 940 that reflects lights from plural collimator lenses 932 (i.e., lights from a solid-state light source array 920) so that distances between optical axes may be made smaller” in addition to the configuration of the related-art light source device as shown in FIG. 9, for example, and already filed it as Japanese Patent Application 2010-268091. According to the light source device of the related earlier application, compared to the light source device in related art, the distances between the optical axes in the lights entering the downstream optical elements can be made smaller, and, as a result, upsizing of the downstream optical elements can be suppressed and reduction in size and weight of the light source device compared to the light source device in related art can be realized.
Incidentally, obtainment of desired color lights by combining solid-state light sources with a fluorescent layer has been widely known. However, in the case where the fluorescent layer is applied to the light source device including the plural solid-state light sources like the light source device in related art, an excessive thermal load may be applied to the fluorescent layer and its life may be made shorter due to deterioration and burnout of the fluorescent layer. In this case, for example, light intensity per unit area of the light entering the fluorescent layer (hereinafter, “light intensity per unit area” will be referred to as “light intensity”) may locally exceed 300 W/mm2 (see FIG. 6D, which will be described later). The inventors of the invention have made mention of its solution in the related earlier application.
Specifically, as shown in FIG. 9, by using additional optical elements such as “a downstream collimator system 961 that is provided at the downstream of a collection system 950 and nearly parallelizes light from the collection system 950, a homogenizer 962 that homogenizes an in-plane light intensity distribution of the light from the downstream collimator system 961, and a downstream collection system 966 that collects the light from the homogenizer 962”, the peak intensity of the light entering the fluorescent layer (shown by the sign 974 in FIG. 9) can be reduced. As a result, the thermal load applied to the fluorescent layer can be suppressed, and the life can be extended by suppression of the deterioration and burnout of the fluorescent layer.
However, in the above described light source device, there is a problem that light use efficiency may be reduced because the light from the solid-state light source reaches the fluorescent layer through many optical elements. Further, there is another problem that reduction in size and weight of the light source device as the original goal becomes difficult because the number of optical elements forming the light source device is larger.